1/*
2 * DECnet       An implementation of the DECnet protocol suite for the LINUX
3 *              operating system.  DECnet is implemented using the  BSD Socket
4 *              interface as the means of communication with the user level.
5 *
6 *              DECnet Neighbour Functions (Adjacency Database and
7 *                                                        On-Ethernet Cache)
8 *
9 * Author:      Steve Whitehouse <SteveW@ACM.org>
10 *
11 *
12 * Changes:
13 *     Steve Whitehouse     : Fixed router listing routine
14 *     Steve Whitehouse     : Added error_report functions
15 *     Steve Whitehouse     : Added default router detection
16 *     Steve Whitehouse     : Hop counts in outgoing messages
17 *     Steve Whitehouse     : Fixed src/dst in outgoing messages so
18 *                            forwarding now stands a good chance of
19 *                            working.
20 *     Steve Whitehouse     : Fixed neighbour states (for now anyway).
21 *     Steve Whitehouse     : Made error_report functions dummies. This
22 *                            is not the right place to return skbs.
23 *     Steve Whitehouse     : Convert to seq_file
24 *
25 */
26
27#include <linux/net.h>
28#include <linux/module.h>
29#include <linux/socket.h>
30#include <linux/if_arp.h>
31#include <linux/slab.h>
32#include <linux/if_ether.h>
33#include <linux/init.h>
34#include <linux/proc_fs.h>
35#include <linux/string.h>
36#include <linux/netfilter_decnet.h>
37#include <linux/spinlock.h>
38#include <linux/seq_file.h>
39#include <linux/rcupdate.h>
40#include <linux/jhash.h>
41#include <linux/atomic.h>
42#include <net/net_namespace.h>
43#include <net/neighbour.h>
44#include <net/dst.h>
45#include <net/flow.h>
46#include <net/dn.h>
47#include <net/dn_dev.h>
48#include <net/dn_neigh.h>
49#include <net/dn_route.h>
50
51static int dn_neigh_construct(struct neighbour *);
52static void dn_neigh_error_report(struct neighbour *, struct sk_buff *);
53static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb);
54
55/*
56 * Operations for adding the link layer header.
57 */
58static const struct neigh_ops dn_neigh_ops = {
59	.family =		AF_DECnet,
60	.error_report =		dn_neigh_error_report,
61	.output =		dn_neigh_output,
62	.connected_output =	dn_neigh_output,
63};
64
65static u32 dn_neigh_hash(const void *pkey,
66			 const struct net_device *dev,
67			 __u32 *hash_rnd)
68{
69	return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
70}
71
72static bool dn_key_eq(const struct neighbour *neigh, const void *pkey)
73{
74	return neigh_key_eq16(neigh, pkey);
75}
76
77struct neigh_table dn_neigh_table = {
78	.family =			PF_DECnet,
79	.entry_size =			NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),
80	.key_len =			sizeof(__le16),
81	.protocol =			cpu_to_be16(ETH_P_DNA_RT),
82	.hash =				dn_neigh_hash,
83	.key_eq =			dn_key_eq,
84	.constructor =			dn_neigh_construct,
85	.id =				"dn_neigh_cache",
86	.parms ={
87		.tbl =			&dn_neigh_table,
88		.reachable_time =	30 * HZ,
89		.data = {
90			[NEIGH_VAR_MCAST_PROBES] = 0,
91			[NEIGH_VAR_UCAST_PROBES] = 0,
92			[NEIGH_VAR_APP_PROBES] = 0,
93			[NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
94			[NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
95			[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
96			[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
97			[NEIGH_VAR_QUEUE_LEN_BYTES] = 64*1024,
98			[NEIGH_VAR_PROXY_QLEN] = 0,
99			[NEIGH_VAR_ANYCAST_DELAY] = 0,
100			[NEIGH_VAR_PROXY_DELAY] = 0,
101			[NEIGH_VAR_LOCKTIME] = 1 * HZ,
102		},
103	},
104	.gc_interval =			30 * HZ,
105	.gc_thresh1 =			128,
106	.gc_thresh2 =			512,
107	.gc_thresh3 =			1024,
108};
109
110static int dn_neigh_construct(struct neighbour *neigh)
111{
112	struct net_device *dev = neigh->dev;
113	struct dn_neigh *dn = (struct dn_neigh *)neigh;
114	struct dn_dev *dn_db;
115	struct neigh_parms *parms;
116
117	rcu_read_lock();
118	dn_db = rcu_dereference(dev->dn_ptr);
119	if (dn_db == NULL) {
120		rcu_read_unlock();
121		return -EINVAL;
122	}
123
124	parms = dn_db->neigh_parms;
125	if (!parms) {
126		rcu_read_unlock();
127		return -EINVAL;
128	}
129
130	__neigh_parms_put(neigh->parms);
131	neigh->parms = neigh_parms_clone(parms);
132	rcu_read_unlock();
133
134	neigh->ops = &dn_neigh_ops;
135	neigh->nud_state = NUD_NOARP;
136	neigh->output = neigh->ops->connected_output;
137
138	if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
139		memcpy(neigh->ha, dev->broadcast, dev->addr_len);
140	else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
141		dn_dn2eth(neigh->ha, dn->addr);
142	else {
143		net_dbg_ratelimited("Trying to create neigh for hw %d\n",
144				    dev->type);
145		return -EINVAL;
146	}
147
148	/*
149	 * Make an estimate of the remote block size by assuming that its
150	 * two less then the device mtu, which it true for ethernet (and
151	 * other things which support long format headers) since there is
152	 * an extra length field (of 16 bits) which isn't part of the
153	 * ethernet headers and which the DECnet specs won't admit is part
154	 * of the DECnet routing headers either.
155	 *
156	 * If we over estimate here its no big deal, the NSP negotiations
157	 * will prevent us from sending packets which are too large for the
158	 * remote node to handle. In any case this figure is normally updated
159	 * by a hello message in most cases.
160	 */
161	dn->blksize = dev->mtu - 2;
162
163	return 0;
164}
165
166static void dn_neigh_error_report(struct neighbour *neigh, struct sk_buff *skb)
167{
168	printk(KERN_DEBUG "dn_neigh_error_report: called\n");
169	kfree_skb(skb);
170}
171
172static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb)
173{
174	struct dst_entry *dst = skb_dst(skb);
175	struct dn_route *rt = (struct dn_route *)dst;
176	struct net_device *dev = neigh->dev;
177	char mac_addr[ETH_ALEN];
178	unsigned int seq;
179	int err;
180
181	dn_dn2eth(mac_addr, rt->rt_local_src);
182	do {
183		seq = read_seqbegin(&neigh->ha_lock);
184		err = dev_hard_header(skb, dev, ntohs(skb->protocol),
185				      neigh->ha, mac_addr, skb->len);
186	} while (read_seqretry(&neigh->ha_lock, seq));
187
188	if (err >= 0)
189		err = dev_queue_xmit(skb);
190	else {
191		kfree_skb(skb);
192		err = -EINVAL;
193	}
194	return err;
195}
196
197static int dn_neigh_output_packet(struct sock *sk, struct sk_buff *skb)
198{
199	struct dst_entry *dst = skb_dst(skb);
200	struct dn_route *rt = (struct dn_route *)dst;
201	struct neighbour *neigh = rt->n;
202
203	return neigh->output(neigh, skb);
204}
205
206/*
207 * For talking to broadcast devices: Ethernet & PPP
208 */
209static int dn_long_output(struct neighbour *neigh, struct sock *sk,
210			  struct sk_buff *skb)
211{
212	struct net_device *dev = neigh->dev;
213	int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
214	unsigned char *data;
215	struct dn_long_packet *lp;
216	struct dn_skb_cb *cb = DN_SKB_CB(skb);
217
218
219	if (skb_headroom(skb) < headroom) {
220		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
221		if (skb2 == NULL) {
222			net_crit_ratelimited("dn_long_output: no memory\n");
223			kfree_skb(skb);
224			return -ENOBUFS;
225		}
226		consume_skb(skb);
227		skb = skb2;
228		net_info_ratelimited("dn_long_output: Increasing headroom\n");
229	}
230
231	data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
232	lp = (struct dn_long_packet *)(data+3);
233
234	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
235	*(data + 2) = 1 | DN_RT_F_PF; /* Padding */
236
237	lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
238	lp->d_area   = lp->d_subarea = 0;
239	dn_dn2eth(lp->d_id, cb->dst);
240	lp->s_area   = lp->s_subarea = 0;
241	dn_dn2eth(lp->s_id, cb->src);
242	lp->nl2      = 0;
243	lp->visit_ct = cb->hops & 0x3f;
244	lp->s_class  = 0;
245	lp->pt       = 0;
246
247	skb_reset_network_header(skb);
248
249	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, sk, skb,
250		       NULL, neigh->dev, dn_neigh_output_packet);
251}
252
253/*
254 * For talking to pointopoint and multidrop devices: DDCMP and X.25
255 */
256static int dn_short_output(struct neighbour *neigh, struct sock *sk,
257			   struct sk_buff *skb)
258{
259	struct net_device *dev = neigh->dev;
260	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
261	struct dn_short_packet *sp;
262	unsigned char *data;
263	struct dn_skb_cb *cb = DN_SKB_CB(skb);
264
265
266	if (skb_headroom(skb) < headroom) {
267		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
268		if (skb2 == NULL) {
269			net_crit_ratelimited("dn_short_output: no memory\n");
270			kfree_skb(skb);
271			return -ENOBUFS;
272		}
273		consume_skb(skb);
274		skb = skb2;
275		net_info_ratelimited("dn_short_output: Increasing headroom\n");
276	}
277
278	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
279	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
280	sp = (struct dn_short_packet *)(data+2);
281
282	sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
283	sp->dstnode    = cb->dst;
284	sp->srcnode    = cb->src;
285	sp->forward    = cb->hops & 0x3f;
286
287	skb_reset_network_header(skb);
288
289	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, sk, skb,
290		       NULL, neigh->dev, dn_neigh_output_packet);
291}
292
293/*
294 * For talking to DECnet phase III nodes
295 * Phase 3 output is the same as short output, execpt that
296 * it clears the area bits before transmission.
297 */
298static int dn_phase3_output(struct neighbour *neigh, struct sock *sk,
299			    struct sk_buff *skb)
300{
301	struct net_device *dev = neigh->dev;
302	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
303	struct dn_short_packet *sp;
304	unsigned char *data;
305	struct dn_skb_cb *cb = DN_SKB_CB(skb);
306
307	if (skb_headroom(skb) < headroom) {
308		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
309		if (skb2 == NULL) {
310			net_crit_ratelimited("dn_phase3_output: no memory\n");
311			kfree_skb(skb);
312			return -ENOBUFS;
313		}
314		consume_skb(skb);
315		skb = skb2;
316		net_info_ratelimited("dn_phase3_output: Increasing headroom\n");
317	}
318
319	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
320	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
321	sp = (struct dn_short_packet *)(data + 2);
322
323	sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
324	sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
325	sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
326	sp->forward  = cb->hops & 0x3f;
327
328	skb_reset_network_header(skb);
329
330	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, sk, skb,
331		       NULL, neigh->dev, dn_neigh_output_packet);
332}
333
334int dn_to_neigh_output(struct sock *sk, struct sk_buff *skb)
335{
336	struct dst_entry *dst = skb_dst(skb);
337	struct dn_route *rt = (struct dn_route *) dst;
338	struct neighbour *neigh = rt->n;
339	struct dn_neigh *dn = (struct dn_neigh *)neigh;
340	struct dn_dev *dn_db;
341	bool use_long;
342
343	rcu_read_lock();
344	dn_db = rcu_dereference(neigh->dev->dn_ptr);
345	if (dn_db == NULL) {
346		rcu_read_unlock();
347		return -EINVAL;
348	}
349	use_long = dn_db->use_long;
350	rcu_read_unlock();
351
352	if (dn->flags & DN_NDFLAG_P3)
353		return dn_phase3_output(neigh, sk, skb);
354	if (use_long)
355		return dn_long_output(neigh, sk, skb);
356	else
357		return dn_short_output(neigh, sk, skb);
358}
359
360/*
361 * Unfortunately, the neighbour code uses the device in its hash
362 * function, so we don't get any advantage from it. This function
363 * basically does a neigh_lookup(), but without comparing the device
364 * field. This is required for the On-Ethernet cache
365 */
366
367/*
368 * Pointopoint link receives a hello message
369 */
370void dn_neigh_pointopoint_hello(struct sk_buff *skb)
371{
372	kfree_skb(skb);
373}
374
375/*
376 * Ethernet router hello message received
377 */
378int dn_neigh_router_hello(struct sock *sk, struct sk_buff *skb)
379{
380	struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
381
382	struct neighbour *neigh;
383	struct dn_neigh *dn;
384	struct dn_dev *dn_db;
385	__le16 src;
386
387	src = dn_eth2dn(msg->id);
388
389	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
390
391	dn = (struct dn_neigh *)neigh;
392
393	if (neigh) {
394		write_lock(&neigh->lock);
395
396		neigh->used = jiffies;
397		dn_db = rcu_dereference(neigh->dev->dn_ptr);
398
399		if (!(neigh->nud_state & NUD_PERMANENT)) {
400			neigh->updated = jiffies;
401
402			if (neigh->dev->type == ARPHRD_ETHER)
403				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
404
405			dn->blksize  = le16_to_cpu(msg->blksize);
406			dn->priority = msg->priority;
407
408			dn->flags &= ~DN_NDFLAG_P3;
409
410			switch (msg->iinfo & DN_RT_INFO_TYPE) {
411			case DN_RT_INFO_L1RT:
412				dn->flags &=~DN_NDFLAG_R2;
413				dn->flags |= DN_NDFLAG_R1;
414				break;
415			case DN_RT_INFO_L2RT:
416				dn->flags |= DN_NDFLAG_R2;
417			}
418		}
419
420		/* Only use routers in our area */
421		if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
422			if (!dn_db->router) {
423				dn_db->router = neigh_clone(neigh);
424			} else {
425				if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
426					neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
427			}
428		}
429		write_unlock(&neigh->lock);
430		neigh_release(neigh);
431	}
432
433	kfree_skb(skb);
434	return 0;
435}
436
437/*
438 * Endnode hello message received
439 */
440int dn_neigh_endnode_hello(struct sock *sk, struct sk_buff *skb)
441{
442	struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
443	struct neighbour *neigh;
444	struct dn_neigh *dn;
445	__le16 src;
446
447	src = dn_eth2dn(msg->id);
448
449	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
450
451	dn = (struct dn_neigh *)neigh;
452
453	if (neigh) {
454		write_lock(&neigh->lock);
455
456		neigh->used = jiffies;
457
458		if (!(neigh->nud_state & NUD_PERMANENT)) {
459			neigh->updated = jiffies;
460
461			if (neigh->dev->type == ARPHRD_ETHER)
462				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
463			dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
464			dn->blksize  = le16_to_cpu(msg->blksize);
465			dn->priority = 0;
466		}
467
468		write_unlock(&neigh->lock);
469		neigh_release(neigh);
470	}
471
472	kfree_skb(skb);
473	return 0;
474}
475
476static char *dn_find_slot(char *base, int max, int priority)
477{
478	int i;
479	unsigned char *min = NULL;
480
481	base += 6; /* skip first id */
482
483	for(i = 0; i < max; i++) {
484		if (!min || (*base < *min))
485			min = base;
486		base += 7; /* find next priority */
487	}
488
489	if (!min)
490		return NULL;
491
492	return (*min < priority) ? (min - 6) : NULL;
493}
494
495struct elist_cb_state {
496	struct net_device *dev;
497	unsigned char *ptr;
498	unsigned char *rs;
499	int t, n;
500};
501
502static void neigh_elist_cb(struct neighbour *neigh, void *_info)
503{
504	struct elist_cb_state *s = _info;
505	struct dn_neigh *dn;
506
507	if (neigh->dev != s->dev)
508		return;
509
510	dn = (struct dn_neigh *) neigh;
511	if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
512		return;
513
514	if (s->t == s->n)
515		s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
516	else
517		s->t++;
518	if (s->rs == NULL)
519		return;
520
521	dn_dn2eth(s->rs, dn->addr);
522	s->rs += 6;
523	*(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
524	*(s->rs) |= dn->priority;
525	s->rs++;
526}
527
528int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
529{
530	struct elist_cb_state state;
531
532	state.dev = dev;
533	state.t = 0;
534	state.n = n;
535	state.ptr = ptr;
536	state.rs = ptr;
537
538	neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
539
540	return state.t;
541}
542
543
544#ifdef CONFIG_PROC_FS
545
546static inline void dn_neigh_format_entry(struct seq_file *seq,
547					 struct neighbour *n)
548{
549	struct dn_neigh *dn = (struct dn_neigh *) n;
550	char buf[DN_ASCBUF_LEN];
551
552	read_lock(&n->lock);
553	seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
554		   dn_addr2asc(le16_to_cpu(dn->addr), buf),
555		   (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
556		   (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
557		   (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
558		   dn->n.nud_state,
559		   atomic_read(&dn->n.refcnt),
560		   dn->blksize,
561		   (dn->n.dev) ? dn->n.dev->name : "?");
562	read_unlock(&n->lock);
563}
564
565static int dn_neigh_seq_show(struct seq_file *seq, void *v)
566{
567	if (v == SEQ_START_TOKEN) {
568		seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
569	} else {
570		dn_neigh_format_entry(seq, v);
571	}
572
573	return 0;
574}
575
576static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
577{
578	return neigh_seq_start(seq, pos, &dn_neigh_table,
579			       NEIGH_SEQ_NEIGH_ONLY);
580}
581
582static const struct seq_operations dn_neigh_seq_ops = {
583	.start = dn_neigh_seq_start,
584	.next  = neigh_seq_next,
585	.stop  = neigh_seq_stop,
586	.show  = dn_neigh_seq_show,
587};
588
589static int dn_neigh_seq_open(struct inode *inode, struct file *file)
590{
591	return seq_open_net(inode, file, &dn_neigh_seq_ops,
592			    sizeof(struct neigh_seq_state));
593}
594
595static const struct file_operations dn_neigh_seq_fops = {
596	.owner		= THIS_MODULE,
597	.open		= dn_neigh_seq_open,
598	.read		= seq_read,
599	.llseek		= seq_lseek,
600	.release	= seq_release_net,
601};
602
603#endif
604
605void __init dn_neigh_init(void)
606{
607	neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table);
608	proc_create("decnet_neigh", S_IRUGO, init_net.proc_net,
609		    &dn_neigh_seq_fops);
610}
611
612void __exit dn_neigh_cleanup(void)
613{
614	remove_proc_entry("decnet_neigh", init_net.proc_net);
615	neigh_table_clear(NEIGH_DN_TABLE, &dn_neigh_table);
616}
617